The present invention relates generally to a method and apparatus for minimizing the emission of particulate-laden smoke to the ambient atmosphere during extrusion of incandescent coke from a coke oven and during the quenching thereof at oven side. More specifically, the present invention discloses a method and apparatus involving a "one spot" container and mating hood including a spraying system operable during extrusion and quenching of the coke. Particulate matter entrained in the resulting steam is removed upon passage of the steam through an inertial impaction vent disposed in the hood portion of the apparatus.
The ever-increasing concern over environmental pollution has focused on a number of industrial operations that emit substantial amounts of gases and particulate matter to the ambient atmosphere. Various gas-cleaning devices such as electrostatic precipitators, scrubbers, etc. have been employed to collect the emissions. However, such devices have generally been applicable for use only in conjunction with fixed or stationary capturing structures. Thus, there is a need for such systems that may be employed wherein vehicular operations are encountered, at least in part and which require emission control.
One particular industrial operation producing substantial gases and particulate emissions is the movement of incandescent coke from a slot oven and the conveyance of such incandescent coke to a remotely located quenching station at which the coke is quenched. Typically, coke is pushed or extruded from any one of several individual oven chambers in a slot-type battery into a movable guide by which the coke is constrained to fall into an open-top railroad vehicle while it is moving past a loading point adjacent to the coke oven. As the coke emerges from the oven, the gases and particulate emissions are relatively minor until the coke begins to break up as it leaves the coke guide to drop into the vehicle thereunderneath. This extruding and falling of the coke normally results in a generation of a substantial quantity of sooty smoke and other particulate matter of the type that pollute the ambient air and atmosphere.
Accordingly, in slot-oven cokemaking air polluting emissions escape during (1) the extrusion process, (2) while incandescent coke is transported to another location for quenching and during (3) quenching of the coke. Subsequent to quenching the cooled coke is discharged from the transiting equipment or vehicle associated therewith so that the same equipment can be used for subsequent cycles. All of the above steps are closely related because of the need to expeditiously handle incandescent coke once it is extruded to the atmosphere, where it begins to burn. The nature of these steps (and their punishing effect on equipment used therefor) are well known and normally repetitious through several cycles each hour. For example, a method and apparatus for controlling particulate emissions during the coke extrusion and transit phases referred to herein above is disclosed and claimed in applicant's U.S. Pat. No. 4,113,569, issued Sept. 12, 1978, and assigned to the assignee of the instant invention.
As considered in applicant's U.S. Pat. No. 4,113,569 water has most commonly been the media used to lower incandescent coke below its ignition temperature. It is well known to the art that some liquid water survives conversion to gaseous steam, even in the presence of excessive heat, because droplets of water or columns of water become covered with steam envelopes which diminish the transfer of heat. In traditional, remotely located quenching processes it is common to use three to four times as much water as is converted to steam, for example. Accordingly, the apparatus and process of the present invention include means for the collection and husbanding of water not converted to steam for reintroduction during subsequent cycles, and to do so without interfering with coke loading and unloading. All recycled water is moved by pumps on board the coke vehicle and reintroduced so as to minimize the known difficulty of quenching coke in the lower, central areas of a relatively deep container.
As considered herein above, traditional wet quenching has been conducted in remotely located towers with large, ground level portals to permit the entrance and exit of rail vehicles containing coke. In attempting to minimize the carryout of solids the steam plumes associated therewith are passed upwardly through inertial impactors to de-entrain water and particulate matter. The flow resistance of such de-entrainment facilities is necessarily kept minimal to minimize or avoid flow through the rail vehicle portals. The result has been marginally satisfactory emission control. In a fully closed apparatus as herein described the inertial impactors will intensify resistance to flow and enhance de-entrainment of water and particulates from exhausted steam.
As described above, air polluting emissions evolve from coke, both when a coke cake is breaking during the extrusion, and from the coke which has come to a position of repose within the container into which it is extruded. To facilitate containment of fume and to permit directing it through a gas cleaner it has been granted to be beneficial to hold the container immobile through the extrusion phase so that fume containing equipment having mating surfaces can directly contact with one another. This has led to the development of the concept of a "one-spot car" in which incandescent coke is contained in a relatively deep, short container. Rather than coke being disposed in a thin layer on the sloped bottom of a traditional long quench car, the newer concept causes problems in coke quenching and adaptations therefore must be incorporated. However, by obviating the time period necessary to move coke from where it is extruded to remote quenching facilities, one of the three hot coke emission periods is eliminated. The necessity to include apparatus devoted to control hot coke transit emissions is obviated along with interface adaptations with traditional or modified wet quenching facilities to accept the transiting car. Obviation of the time necessary for incandescent coke transit also permits lengthening and subduing the instantaneous intensity of the quenching process.